Organic light emitting diodes are a promising solid-state lighting technology, combining area emission with a robust, flat structure well adapted to area illumination. Organic light emitting diodes (OLEDs) are manufactured by depositing organic semiconductor materials between electrodes on a substrate.
Referring to FIG. 12, an OLED device 10 includes a substrate 100 on which are deposited a first electrode 110, one or more organic layers 120, for example including a hole-injection layer, a hole-transport layer, a light-emitting layer, an electron-transport layer, an electron-injection layer, and a second electrode 130. An encapsulating cover 140 protects and seals the OLED device 10. Light 200 is emitted from the device either through the cover 140 (as shown) or through the substrate 100 (not shown) depending on the composition and transparency of the substrate 100, cover 140, and electrodes 110 and 130. Electrode contacts are electrically connected to the electrodes 110 and 130 to connect the OLED to a power source. A great variety of OLED devices, structures, organic layers, and material composition are described in the art. Such OLED devices enable the creation of light sources having extended surface area on a single substrate. The prior art describes the use of OLED devices in conventional lighting (for example U.S. Pat. 6,819,036 entitled “OLED Lighting Apparatus” by Cok, issued Nov. 16, 2004).
The lighting industry employs ceiling grids with luminaires, typically employing fluorescent lights, interspersed with fiber-composition panels in a suspended ceiling. For example, US20020136001 A1 entitled “Low-profile fluorescent luminaire and methods of installation” describes a low-profile fluorescent luminaire for attachment to a suspended ceiling and methods for retrofitting the luminaire to an existing lighting system. The low-profile fluorescent luminaire has lightweight “I”-shaped framework comprising a pair of transversely-extending end plates attached adjacent to opposed longitudinal ends of a longitudinally-extending spine. The spine and the end plates have a substantially coplanar arrangement to provide a low-profile structure that closely conforms to the ceiling. The “I”-shaped framework supports a reflector positioned below the spine and end plates when the luminaire is in a supported functional position. The low-profile luminaire can be retrofitted to a suspended ceiling to replace the existing light fixtures or to supplement the light output of an existing lighting system without modifying or removing the existing lighting fixtures. U.S. patent application Ser. No. 10/978,190 filed Oct. 29, 2004 entitled Heat Conducting Mounting Fixture for Solid-State Lamp by Giana Maria Phelan et al. describes the use of OLED lamps in a suspended ceiling and employs a thermally conductive mounting member and is hereby incorporated in its entirety by reference.
U.S. Pat. No. 3,504,172, granted Mar. 31, 1970, discloses a lighting fixture support and display device comprising an elongated channel having a top wall, vertically disposed side walls and a downwardly facing opening, said channel having an upper channel section and a lower channel section, an elongated plate disposed within said channel closing the upper channel section, means carried by said vertically disposed side walls engaging and supporting said plate, engagement of the last said means and said plate preventing outward displacement of said side walls, said plate having a plurality of openings spaced along its length and downwardly facing electric outlets carried in said openings, said upper channel retaining electric wiring for connecting said outlets to a source of electric energy, inwardly formed flanges carried by the lower edges of the side walls of said lower channel section, and a plurality of elongated closure elements removably carried in end to end relationship by said inwardly extending flanges to close said lower channel section, at least certain of said closure elements having openings for attachment of a pendant lighting fixture and switch means thereto, said fixture being provided with a plug for engaging one of said outlets to energize said fixture. However, there is no disclosure of providing power to flat-panel lamps in the fixture.
An important feature of suspended ceilings is the cost of removing or replacing faulty panels, particularly lamps mounted in the suspended ceilings. However, as described in the prior art, flat-panel lamps are not suitable for providing a simple and removable design for suspended ceilings. There is a need, therefore, for a flat-panel illumination system useful in suspended ceilings and providing a simple, safe, and reliable means of replacement and power distribution.